Hydraulic properties determination from pumping test in Northern areas of Ondo state, South-western Nigeria for groundwater development

Abstract

Groundwater potential evaluation of the Northern area of Ondo State using information obtained from hydrogeological measurements of hydraulic conductivity, transmissivity, and yield aquifer characteristics from 37 drilled boreholes. These data were analyzed alongside the information gathered during the pumping test at each site which includes drawdown values, static water level, and pumping rate. The average depth of the borehole and installation depth are 30.76 m and 28.9 m respectively. The static water level ranges from 2.7 m to 14.0 m with an average of 6.0 m. The drawdown recorded from the observation wells varies from 1.9 m and 15.1 m. The yield capacity of the boreholes ranges between 0.40 – 2.98 L/s, and an average of 25.5654 m3/d. The values of hydraulic conductivity conducted in the area vary from 0.37 to 23.29 m/d, and an average of 3.67 m/d. The calculated transmissivity for the study area ranges from 4.79 (gneiss) to 165.32m2/d (migmatite) and an average of 30.08m2/d. The values of specific capacity vary from 4.07 – 140.53, while storativity within the range of 0.0002 – 0.001 are the most dominant showing a corresponding low specific capacity values generally less than 10 m2/d. Consequently, specific yield, hydraulic conductivity, and transmissivity values were integrated to generate a groundwater potential map for Ondo Northern area.